In general, at the time of a civil engineering and construction work, the ground is first excavated and a walling temporary facility is installed in order to prevent the collapse of the ground. Thereafter, construction is carried out.
The walling temporary facility is installed using a spread beam method or a ground anchor method. An H-beam type wale is perpendicularly installed inside a horizontal spread beam to support the spread beam.
However, in the walling temporary facility having the aforementioned structure, loads are concentrated on the horizontally-installed wale. Thus, if a local buckling phenomenon occurs in the wale, a ground sinking or collapse accident may be generated.
Specifically, when a shear stress is excessively generated in the wale, buckling occurs in the wale. This leads to deformation and shear failure of the wale.
As a result, an eccentric load acts on the horizontally-installed spread beam. Thus, there may be generated an accident in which a screw jack is destroyed and a walling temporary facility is collapsed.
In order to solve the above problem, wale-reinforcing stiffeners are installed in the wale of the walling temporary facility at predetermined intervals in order to prevent local buckling caused by a shear force and to secure strength.
In the case of the aforementioned wale-reinforcing stiffeners, typically, a steel plate is processed in conformity with the standard of a wale having an H-beam shape and is welded between the flanges of wales by fillet welding.
This poses a problem in that a great deal of time is consumed in installing the wale-reinforcing stiffeners.
For the aforementioned reason, in a construction site, there may be a case where a wale-reinforcing stiffener is not installed at all or a case where a stiffener is installed only in the upper portion of a wale that can be visually checked.
Thus, there is a problem in that the deformation and collapse of the walling temporary facility, the sinking of the rear surface portion and the like occur.
Furthermore, according to the conventional method in which the reinforcing stiffener is attached to the wale by welding, the stiffener cannot be reused and is therefore uneconomical. After the stiffener is installed, it is difficult to change the position of the stiffener. In addition, there is a problem in that the labor cost is increased due to the fillet welding work.
Moreover, the steel plate needs to be separately processed in conformity with the size of the wale. The lower portion of the wale has to be subjected to upward welding. This leads to a problem of reduced installation quality.
In addition, at the time of the welding work of the stiffener, there may be generated an accident in which a worker falls down or undergoes electrical shock. There is also a possibility of explosion. If a worker performs works for a long time in an unstable posture, a problem is posed in that the worker may suffer from a muscular skeletal disease.
In order to solve the problems of the weld type stiffener, various non-weld type stiffeners have been developed and used.
According to the non-weld type stiffeners, it is possible to solve the problems inherent in the weld type stiffener described above.
However, the conventional non-weld type stiffeners have a problem in that it is difficult or impossible to adjust the length thereof, which makes it impossible to generally use the non-weld type stiffeners.
In addition, some of the conventional non-weld type stiffeners cannot be installed or are difficult to install in a specific section. It is also inconvenient to adjust the length thereof using a spanner.